\( \newcommand{\cat}[1] {\mathrm{#1}} \newcommand{\catobj}[1] {\operatorname{Obj}(\mathrm{#1})} \newcommand{\cathom}[1] {\operatorname{Hom}_{\cat{#1}}} \newcommand{\multiBetaReduction}[0] {\twoheadrightarrow_{\beta}} \newcommand{\betaReduction}[0] {\rightarrow_{\beta}} \newcommand{\betaEq}[0] {=_{\beta}} \newcommand{\string}[1] {\texttt{"}\mathtt{#1}\texttt{"}} \newcommand{\symbolq}[1] {\texttt{`}\mathtt{#1}\texttt{'}} \)

Covariance

Let \( (\Omega, \mathrm{F}, \mathbb{P}) \) be a discrete probability space let \( X: \Omega \to S_x \) and \( Y : \Omega \to S_y \), be two random variables, where \( S_x\) and \( S_y \) are finite subsets of \( \mathbb{R} \). Then the covariance of \( X \) and \( Y \) is defined as the mean of the following random variable:

In terms of \( X \) and \( Y \), the calculation for covariance is thus: